Power Siphon generating more than 1 charge per kill.

I posted this in the power siphon feedback thread, thought might as well start a new thread so I can organize more easily.

This comes to my attention when I sometimes generates more power charge than frenzy charge. (and I always cast blood rage before engaging the monster, so they should at even number)

Here's a video:
http://youtu.be/dn4xeGQkKTE

At the end of video, I have only killed 2 snakes and 1 totem (1 snake ran away), but I generated 5 power charges and only 3 frenzy charge. At some point during the process, the game count 1 kill as 2, and gave me 2 charges instead of just one.

My guess at this is that when you crit, the burning damage will kill the monster on the same time as culling strike takes effect.

p.s I tried reproducing this in lower level (where I would 1hko any monster), and have little luck of gaining more charges than I should. This 2 charges per kill only become obvious when farming in higher level areas.

I have noticed this too, but I wasn't dual wielding. Since you're dealing lightning damage as well (I see Wrath), it could have something to do with monsters being shocked. Here's my earlier thread that probably got ignored: http://www.pathofexile.com/forum/view-thread/39328

Mark explained in the power siphon feedback thread stating that attack speed is giving the double effect, and likely will be fixed.